Update SDK (v0.5.7)
Update SDK (v0.5.7)

u-engine/cardboard-java,jqyp324/-test_cardboard,hassank/Wanderer,MaTriXy/cardboard-java,bobbyang1/testytest,farinhite451/Cardboard-Java,googlesamples/cardboard-java,hassank/Wanderer,n-eisner/GoogleCardboard,hassank/Wanderer